I've done it via Stornoway and coming onto Harris. Don't remember there being that much difference in cost - but was doing island hopping so that might have had an influence.

I would imagine it can be done without a car, like Tombo said, the buses do run regularly but stop pretty early in the day.

This time of year, you're not going to have too much light, and if you have work stuff to do too then your 'staying over' plan would seem the best option.

The crossing can be choppy enough late holiday season, so I can imagine it can get pretty bad if you hit unlucky. Just remember to watch the horizon if you want to hang onto your dinner.

Callanish is so much more than just the main site, so expect to do a fair bit of walking to make the most of your trip. Personally, I would opt for the car to get to some of the outlying sites - just don't get stranded on a Sunday!

Dropping in on Ron & Margaret Curtis is an essential for an understanding of the place - not sure what sort of health they are in though, haven't heard from them for a while. If you go see them pay for one of their tours and take it all in - just don't expect them to be erm conventional.

One way or another you've got to do it.

moey

PS - you were asking about facilities recently - there's a cracking chinese takeaway in Stornoway across from the ferry terminal ;O)